The execution stage of the budget is when revenues are obtained and raised and budgetary expenditures carried out during the fiscal year (from 1 January to 31 December). Amendments or modifications to the revenues and expenditures initially approved in the budget (initial budget estimates) are made during this stage, giving rise to what is known as the final budget. The modifications that may arise in the budget respond to certain types and elements specifically established by the Local Finances Act and budgetary-stability regulations.

Necessary controls are also carried out during the implementation stage, to enable verification (and implementation of corrective measures, where necessary) of compliance with the financial goals of the budget and the planned initiatives and projects.

Once the fiscal year has ended, the City Council's annual accounts are drawn up and the annual financial reports compiled.